Safety device for absorption refrigerators



1943- R. E. scHuRTz El'AL 2,337,067

SAFETY DEVICE FOR ABSORPTION REFRIGERATORS v Filed Dec. 12, 1940 2Sheets-Sheet l Dec; 21; 1943- R. E. SCHURTZ ETAL 2,337,057

: SAFETY DEVICE FOR ABSORPTION REFRIGERATORS Filed Dec. 12, 1940 2Sheets-Sheet 2 name use; 21. 1943 UNITED srAr-Es P-ATENr OFFICE sumDEVICE roa ansoamon anrardaaa-roas,

tion of Michigan Application December 12, 1940,; Serial No. seas-1s 14Claims. (ores-) This invention relates to a safety device for absorptionrefrigerators, and more particularly to a single device responsive toany one of a number of abnormal conditions in a continuous absorptionrefrigeration system 'to hut offfuel flowto a burner.

One feature of this invention is that it provides complete safety for anabsorption refrigeration system left uninspected for considerableperiods of time; another feature of this invention .is that a singlesafety device replaces a number of independent and completely separatesafety devices previously used; afurther feature of this invention isthat it converts pressures into mechanical force and balances theseforces in such a way that any abnormal increase or decrease of any orall of these pressures effects actuation of the safety element;other'features and advantaxes of this invention will be apparent fromthe following specification and the drawings, in which:

Figure 1 is a schematic diagram of a refrigeration system with whichthis invention flndsparticular use; Figure 2 is a top plan view, partlybroken away, of the safety device shown diagrammatically at the bottomof Figure 1; Figure 3 is a vertical sectional view along the line 3-3 ofFigdevice; and Figure, 5 is a horizontal sectional view along the line5-5 of Figure 1.

While the safety device particularly illustrated herewith is adaptableto a number of different uses and systems, it has been foundparticularly useful in connection with a continuous absorptionrefrigeration system, such a system being shown schematically inFigure 1. In order to better understand the operation and advantages ofthe by any convenient means, as the burner il, supplied with fuel, asgas, through the conduit l2.

Refrigerant vapor passes up the pipe I3, through a water-cooledrectifier it, to a water-cooled condenser I 5. The condensed refrigerantvapor then 7 passes upthrough the pipe It to a receiver i'l where anexpansion-valve, here shown as of the conventional float actuated type,controls its admission at greatly reduced pressure to the evaporator orcooling coils l8. The expanded refrigerant vapor then passes through acheck valve i9 and bubbles out into weak liquor in the absorber' 20.Cooling water admitted through the pipe 2| cools the condenser l5,passes through a,

cooling coil 22 in the absorber, next flows through the rectifier l4,and is finally discharged through the pipe 23.

In order to keep the proper quantity and concentration of liquor invarious parts of the system it is necessary to have some flow pathbetweenthe absorber and the still to deliver weak liquor to th absorber.and return rich liquor to the still. Since movement from the still tothe absorber is from a high pressure to a low pressure portion of thesystem, this may be conveniently effected. It is here accomplished bypassing weak liquor out through a pipe 23, through ure 2; Figure 4 is anend elevation of the safety safety device the entire refrigerationsystem will be described briefly. It will be understood, how? ever, thatthe present application is directedprimarily to the-safety device andthat other features and improvements of'the ystem are more particularlydisclosed and claimed in our othercopending joint and sole applications,the earlier flied of such applications being Serial No. 298,110,

flled October 5, 1939; Serial No. 296,995, 'flled September 28, 1939;Serial No. 314,704, filed January 19, 1940; Serial No. 319,541, filedFebruary 17, 1940; Serial No. 326,292, filed March 27, 1940; and SerialNo. 352,328, filed August 12, 1940.

Referring now more particularly to Figure 1, the refrigeration systemschematically illustrated is particularly designed for commercial work.A still l0 contains a mixture of refrigerant and absorbent, a ammoniaand water, and ismheated snap-acting mechanism better shown in Figure 5the coil 24 in the heat exchanger 25, through the pipe 26, the valveassembly 21, and the pipe 28 into a pan in the top of the absorber,overflow from this'pan replenishing the main body of liquid in theabsorber. In order to effect an interchange of liquid between theabsorber and still when the concentration in the still has boiled downto a desired minimum strength a fluid thermostat bulb 29 deliverpressure generated in it through a liquid actuating leg 30 to a bellowschamber in the actuating part of the valve assembly 2]. Here pressure inthe actuating leg is balanced against still pressure delivered throughthe pipe 23 and the valve controlling flow from the-pipe 26 to the pipe28 opens and closes at appropriate intervals.

The return circuit from the absorber to the still is somewhat morecomplex. When the level.

of liquid in the absorber reaches the overflow point 3| it drains downpast the check valve 32 through another valve assembly 33, and throughthe pipe 34 into a transfer chamber 35. A float 36 in the transferchamber is operated through to actuate a rod 31 in the pipe 3| to movethe valve: member in the valve assembly 33, which may be of the plungertype.

In one setting of the valve in the unit 33 the the snap action mechanismpipe 38 is connected to the pipe 34, as before described, to permit flowof liquid into the lower part of the transfer chamber; and the pipe 39is connected to the pipe 46 to vent gas from the top of the chamber tothe absorber. When the chamber has practically filled the upwardmovement of the float snaps the actuating rod 31 up to the positionshown in the drawings, and in this position pipe 4| leading from thebottom of the transfer chamber is connected through the valve unit 33 topipe 42, the flow path proceeding through the heat exchanger 25, thepipe 43, a jacket 44 around the thermostat bulb 29, and thence into thebody of liquid already in the still. In order to equalize pressure inthe transfer chamber and permit a gravity fiow of liquid in thisposition of the valve the pipe 39 at the top of the chamber is connectedto the pipe 45 which is open to high pressure vapor in the pipe [3,being in communication with it at the latters entrance to the condenserl5. As the liquid drains out of the transfer chamber and back to thestill the float 36 drops until the point is reached where is unbalanced,whereupon the rod 31 moves down to its lower position placing thetransfer chamber in communication with the absorber to refill it.

In order to accomplish the desired snap action so that the valves in theunit 33 will never be in an intermediate position, and referringparticularly to Figures 1 and 5, it will be seen that the float isconnected by a link 46 to a fork member 41 pivoted at 48. The ends ofthe legs of the fork 41 are pivoted at 49 to a smaller fork member 50,the actuating rod 31 being pivotally connected to the apex of thislatter fork member. A coil spring has one end fastened to the apex ofthe fork member 56 and the other end to an appropriate point on the wall52, the spring being under tension at all times. It will be readilyapparent that when the fioat is in the position shown in Figure 1 thespring 5| will maintain the actuating rod 31 and the plunger at the topof it at the top of its stroke. As the float 36 falls in the chamberwith discharge of liquid therefrom the position of the actuating rodwill not change until the pivot points 49 connecting the two forkmembers have passed up slightly above the center line of the spring 5|;but as soon as this takes place the spring will become effective to pullthe actuating rod 31 and the plunger valve moved thereby to the lowerend of ,their stroke.

As has been heretofore said, other features and improvements in thesystem in general are the subject matter of earlier filed copendingapplications and other applications now being prepared, so that withthis description of the system in general attention .will be now turnedmore specifically to the safety device 53 shown in two parts in Figure 1for greater clarity of illustration and in detail in Figures 2, 3 and 4.

The safety device comprises a main body portion, as the casting. 54,through which the gas pipe or fuelconduit l2 passes, as may be best seenin Figure 3. Valve means is provided within the device, comprising thevalve member 55 movably mounted and having its valve head adapted tocome into engagement with a valve seat 56 to close the conduit, Meansfor sealing the movable valve member to prevent loss of gas is hereshown in the form of a bellows 51; and a spring 58, lying within thebellows, urgesthe valve member in a downward direction, tending to moveit to closed position. Latch means, which will now be described,normally retains the valvememberln an open position so that there isuninterrupted flow of fuel to the burner: but as soon as the latch meansis moved to released or un- 5 latched position the valve closes underthe influence of the spring 58, thus cutting off fuel flow to theburner. In order to achieve the desired latching action a pivotallymounted pawl or dog 59 on the shank of the valve member, normallymaintained in the position shown in Figure 3 by the spring 69, engages ashoulder or stop piece 6| mounted on a movable member 62. in engagement,as shown in Figure 3, the valve member is mounted in open positionagainst the urging of the spring 58; but any movement'of the member 62which moves the stop piece 6| out from under the pawl 59 unlatches thevalve member\and permits it to move them to closed position. Since thepawl is of the spring-pressed pivotal type, the valve may be easilyreset by pulling up on the finger ring 63 until the posi-- o casting 54.

The movable member 62 is mounted for both rockable'and bodily movement.Rockable movement is about the mounting pin 66 as an axis; and'bodilymovement to the left (speaking with respect to Figures 2 and 3) iseffected by slideable movement of the mounting bar 61 against theresistance of the spring 68. In addition to the spring 68 which resistsbodily movement, springs 10 and 1| act through pins 12 and 13 on anextension 14 of the member 62 to provide resistance to rockablemovement, although such movement is permitted when the resistance ofeither spring is exceeded.

The application of force tending to move the member 62 is through twopointed pins 15 and 116, these pins being attached to the movable headof bellows or Sylphons Tl and 18, respectively. Stationary heads 19 andso are fixedly mounted in the casting 54, these heads being providedwith female portions 8| and 82 which receive male guide portionsextending back from the movable Sylphon heads, as the guide portion 83.Fluid under pressure is admitted through the pipes 84 and 85 to thebellows, passing along a slot provided in the male guide members. Itwill be readily apparent that as long as the pressures in the twoSylphons are approximately equal and their combined pressure is lessthan 50 the resistance of the spring 68 the member 62 will remain in theposition shown in the drawings, holding the valve member latched in openposition. Should the pressure in one Sylphon rise without acorresponding rise in the other (or, to the same 'eil ect, if onepressure should drop without a corresponding drop in the other) theforces would no longer balance each other and the member 62 would rockto the right or left about the pin 66, either movement serving 70 tomove the stop member 6| out from under the pawl 59, whereupon the valvemember moves to closed position under the urging of the spring 58. Thatis, such rocking movement of the member 62 is effected as soon as theforces are unbal- 76 anced to an extent sufficient to overcome the Whenthese two parts are,

opening in the giiide bracket 65 mounted on the resistance of one of thesprings or II. Similarly, should bothpressures rise equally but to anundesirably high extent their combined force would exceed theresistancefof the spring 68 and the entire member 62 would move bodilyto the left, again moving the stop member 6| out from under the pawl 59and letting the valve member move to closed position. Minor differencesin pressure, or fairly similar and simultaneous increases or decreasesof pressure within reasonable ranges, do not effect movement of themember 62, so that the unlatching action takes place only upon abnormalconditions. I

Turning'now more particularly to Figure 1, it will be seen that the tube84 connects to the liquid actuating leg lll leading from the fluidthermostat 29, so that the pressure in the Sylphon i 11 is thepress'urein the thermostat 29, a function of still temperature. Theother tube 85 is shown connected to the high pressure vapor side of thesystem, being connected to one end of the con- ,denser ii, the "pressurein the Sylphon "therefore being a function of highpressure refrigerantvapor in the condenser. If the refrigeration system is working properlythe fluid thermostat pressure will rise slightly above still pressureand then drop slightly below it as transfers are effected; and as roomtemperatures or refrigera- I tion loads vary both pressures will risetogether or fall together approximately similarly. The

" resistance of the spring 68 of the safety device is adjusted to besufficiently high to resist the forces on the member 82 by the pressuresin the still and thermostat bulb within safe operating ranges, as thefull intended refrigeration capacity of the system at a 1i0-degree roomtemperature; and the resistance of the springs 10 and 'Il would be madesufficient to prevent rocking movement of the niember 82 in the normalfluctuations of the thermostat bulb pressure above and below stillpressure.

Should any of the system conditions become abnormal and present possibledanger, however, the safety device goes into operation to shut off thefuel supply. It will be apparent that if both pressures roseexcessively, as upon a failure of condenser water flow, the member 62would be moved bodily to the left to effect the desired unlatchingaction. Similarly, if the transfer mechanism failed to function and theconcentration in the still kept boiling down, the excess of pres- Weclaim: 1

1. 'A safety device for controlling the fuel flow in an absorptionrefrigeration system, including: a flow control valve adapted to belatched open; movable ,means actuated by one condition or the system; asecond movable means actuated by another condition of the system; andsafety means operatively associated with both of said first mentionedmeans andadapted to be moved, when either of said conditions of thesystem becomes abnormal, to effect unlatching and closure of said valve.

2. A safety device for an absorption refrlger ation system, including:movable means actuated by one condition, of the system; a second of thesystem; means for balancing said means against each other; and safetymeans opera tively associated with the balancing means and adapted to bemoved when either of said conditions of the system becomes abn rmal.

3. A safety device for controlling t e fuel flow in a continuousabsorption refrigeration system having a still and other elements,including: a flow control valve adapted tobe latched open; movable meansactuated by one condition of the system, said condition being still.pressure; movable means actuated by another condition of the system,said condition being still temperature; and safety means operativelyassociated with both of said first mentioned means and adapted to bemoved, when either of said conditions of the system becomes abnormal, toefiect unlatching and closure of said valve.

4. A safety device for a continuous absorption refrigeration systemhaving a still and other elements, including: movable means actuated by'one condition of the system, said condition being still pressure;movable means actuated by another pressure condition of the system;means for balancing said means, against each other; and

safety means operatively associated with the balsure in the thermostatbulb over the still pressure 'in the unit 21 to open, rupture of anypipe on the high pressure side of the system, or any of a' number ofother abnormal conditions presentingpossibility of danger would causeeither an unbalancing or an excess of pressure in the safety deviceSylphons, and result in operation of the safety device to shut down thesystem untilit can be given proper attention.

. While we have shown and described certain embodiments of ourinvention, it is to be underancing means and adapted to be moved wheneither of said conditions of the system becomes abnormal.

5. Apparatus of the character claimed in claim 4, wherein the othercondition is the pressure in a fluid thermostat exposed to stilltemperature.

6. A safety device for an absorption refrigeration system, including:movable means actuated by one condition 'of the system; a second movablemeans actuated by another condition of the system; valve means includinga seat and a movable valve member; spring means urging the valve memberin one direction and latch means normally maintaining the valve memberin a desired position against the urging of the spring, the latch meansbeing operatively associated with both first mentioned movable means andadapted pressure; movable means actuated by another stood that it iscapable of many modifications.

Changes, therefore, in the construction and arrangement may be madewithout departing from the spirit and scope of the invention asdisclosed in the appendedclaims.

condition of the system; valve means including a seat and a movablevalve member; spring means associated with both first mentioned movablemeans and adapted to be moved to unlatched position by an abnormalcondition of the system.

wherein the valve means controls the supply of fuel to the burner.

9. A safety device for a continuous absorption refrigeration systemhaving a still and other elements, including: movable means actuated byone condition of the system, said condition being still pressure;movable means actuated by another condition of the system; means forbalancing said means against each other; valve means including a seatand a movable valve member; spring means urging the valve member in onedirection; and latch means normally maintaining the valve member in adesired position against the urging of the spring, the latch means beingoperatively associated with the balancing means and adapted to be movedto unlatched position by an abnormal condition of the system.

10. A safety device of the character described including: a membermounted for rockable movement; pressure actuated means tending to rocksaid member in one direction; a second pressure actuated means tendingto rock the member in the opposite direction; and an element operativelyassociated with the member and adapted to be moved as a result ofmovement of the member when either pressure actuating said means be--comes abnormal.

11. A safety device of the character described including: a'membermounted for rockable and bodily movement; pressure actuated meanstending to rock said member in one direction; a second pressure actuatedmeans tending to rock the ment in one direction; and late -member in theopposite direction; a movable element; spring means urging the elementin one direction; and latch means normally maintaining the element in adesired position against the urging of the spring, the latch means beingoperatively associated with said member and movable to unlatchedposition by any movement thereof.

.12. A safety device of the character described including: a membermounted for rockable and bodily movement; pressure actuated meanstending to rock said member in one direction; a second pressure actuatedmeans tending to rock th member in the opposite direction; increase inpressures actuating both said means tending to effectbodily movement ofsaid member; spring means resisting movement of said member; a movableelement; spring means urging the elem ans normally maintaining theelement in a desired position against the urging of the spring, thelatch means;

being carried by said member and movable to unlatched position by anymovement thereof.

i 13. Apparatus of the character claimed in claim 12, wherein themovable element is a normally open valve member adapted to move intoengagement with a seat when unlatched.

14. Apparatus of the character claimed in claim 9, wherein the valvemeans controls the supply of fuel to a burner adapted to heat the still,and the other condition of the system is still temperature.

RALPH E. SCHURTZ. JOSEPH N. ROTH,

